Tape for slide fasteners



J. E. FI TEJJR TAPE FOR SLIDE FASTENERS Filed Feb. 29, 1944 V r 1 I 2 Mayzs, 1946.

Patented May 28, 1946 UNITED STATES PATENT OFFICE TAPE FOR suns FASTENERS John E. Fite, Jr., Philadelphia, Pa. Application February 29, 1944, Serial No. 524,500

8 Claims.-

This invention relates to slide fasteners, and more particularly to the textile tape employed as the foundations thereof.

A. slide fastener normally includes a pair of parallel foundation tapes. These tapes are composed of textile fabric and one edge of each of the parallel strips is thickened, and thereby reinforced. Usually thi reinforcement consists of a cord laid on each of the opposite faces of the tape, and semi thereto by a row of stitches passing through the two cords and the tape fabric.

posed in a common plane, with the reinforced scoop-bearing edges of the two tapes in close laterally adjacent relation to each other and with the scoops of the respective tapes in alternating interlocking relation.

Each fastener also includes a metal, plastic or other slide, which is employed for engaging and disengaging the scoops. This slide is mounted in a manner to ride on the interlocked scoops. with a minimum amount of rubbing action on the tapes adjacent the inner ends of the scoops.

It has been common practice heretofore, to form the foundation tapes of yams composed exclusively of combed cotton fibres, and to make the tape fabric of one or two ply thicknesses. Normally the widths of these tapes range from of an inch to 13 inches. The tapes are woven with various numbers of picks of-the fllling'or weft threads per inch, warpwise of the tape fabric, and various numbers of warp ends per inch, weftwise of the tape fabric, in accordance with the size and quality of the yarns employed,

'- in order to provide a sufficient degree of firmness in the tape for supporting the scoops in proper position to enter the guide tracks in the slide: to Provide a high degree of tensile strength in the tape; and togive the tapes satisfactory wearing qualities for enduring the hard usage to which the slide fasteners are frequently subjected. r

In many instanceamanufacturers of slide fasteners have encountered considerable difllculty yfibres, in that the tapes tend to wrinkle or 'un-' dulate and become unsightly along the scoopbearing edges thereof. The undulations in the tapes interfere with the smooth normal functioning of the slide in effecting engagement and disengagement of the scoops.

Analysis indicates that the unsightly troublesome wavy conditions which develop in slide fasteners in the course of use arises from a longitudinal shrinking of the foundation tapes. This shrinkage causes the scoops to be drawn into more closely spaced relation to each other. and the resultant reduction in the spacing of the scoops requires the expenditure of greater effort in order to efiect the interlocking action of the scoops, by the slide. This causes the slide to work with a jerky action.

The reduction in the spacing of the scoops. together with the pressure exerted on the edge of the tape as a result .of the scoops being pinched around the reinforced corded edge ,of the tape, restricts the shrinkage of the scoop-bearing edge of the tape, while throughout the remainder of its width, the tape is unrestricted and free to shrink in all directions. Consequently. a shrinkage difierential isset up between the scoopbearing edge of the tape and the remainder of the width of the tape fabric.

The shrinkage differential between the imme diately adjacent portions of the tape develops an internal force in the free portion of the tape A adjacent the restricted reinforced edge portion of the tape, which reacts perpendicularly to the normal plane of the tape in the reinforced edge portion thereof, under the contractive force of shrinkage lengthwise of the tape. This condition results in the scoop-bearing edge of the tape being forced out of the normal plane of the tape into a series of undulations along the length of the tape.

The primary object of the present invention is to produce a tape for use as the foundation of a. slide fastener which will remainflat at all times. The construction of the tape forming the subject matter of the present invention will be fully disclosed hereinafter, reference beinghad to the accompanying drawing, of which:

Figs. 1 and 2 diagrammatically illustrate, on a. greatly, enlarged scale, a face view and typical transverse sectional view respectively of a slide fastener employing foundation tapes made in acwith the tapes composed of the combed cotton cordance with the present invention.

Primarily the invention resides'ln the proper selection of material for the production of the tape. To thi end, the material best suited for i vary relatively in the tapes 2 2,400,924 the purpose of the present invention, and which arrangement affords considerable relative movehas proven to meet all the requirements, is high ment between the adjacent longitudinalareas al,

tenacity synthetic filament, including rayon or nylon, of 1%, denier (approximately 3,952,704 yards per pound), or finer, reduced to staple lengths of not less yarn of two or three ply twist.

,Of' equal importance is the particular weave employed. To this end, a. conventional four leaf twill weave has proven to be best suited to the purpose of the invention.

The tape of the present invention is woven, for example, in five standard widths, namely,

%",1a". 1%", and 1".

The thickness of the tape, is also of importance.

and in all instances, regardless of width, the tape is confined to a thickness not less than .010" or greater than .028". r

The number of picks of filling per inch, throughout the length of the tape, and the number of warp ends per inch, throughout the width of the tape, may be substantially equal, or may of different widths.

In the present instance it is preferable to employthe maximum number of warp ends which can be conveniently handled in the weaving process within the width of the particular fabric being woven, thus the number of warp ends per inch of the width of the tape may vary in the tapes of different standard widths. I

Using the maximum number of warp ends in a given width of tape and a substantially corresponding number of filling or, weft threads in each unit of the length which is equal to the width of particular strip being fabricated, under the four leaf twill weave, provides a tape of maximum texture having a maximum amount of flexibility or fiaccidity over the entire area of the strip, and affords a in the plane of the tape, particularly in that portion of the tape lying between the inner side of the corded edge reinforcement located adjacent the one edge of the tape fabric and the opposite free edge of the tape fabric.

The following table is provided to illustrate relative differences in the tapes of different widths.

' Width, inches it i M Me it heavy 1 Warp-B. 8.. ....pounds 40 60 80 100 110 120 Weft-B. S -.do 60 110 150 150 200 150 Thickness "inches" 0.10 .019 .019 .019 .025 .019 Number of warp ends.... -48 48 60 84 59 112 Number of watts per inch. 64 56 66 56 1 42 56 1 p 1 Double.

In the accompanying drawing, the foundation tapes are designated as Al and A2 respectively.

Each tape is thickened along one edge. as indicated at a, a.

The scoops b, b are of usual construction and are pinched or otherwise set to grip the thickened edges a, a of the tapes firmly at relatively spaced points longitudinally of the tapes. The slide B,'

likewise, is of usual construction and cooperates with the scoops b, b to effect engagement and disengagement thereof, in the usual manner.

The conventional four leaf twill weave produces in the fabric four parallel longitudinal areas al, a2, a3 and .a# respectively, in a herring-bone P than 11% inches and spun into i a2, a3 and at, within the body of the tape, in the plane X-X (Fig. 2) of the tape fabric, longitudinally of the tapes, and this construction, functioning in this manner, permits the tapes to give and take longitudinally with any shrinkage or stretching of the fabric of any article to which the foundation tapes may be secured.

The material employed, 1. e. the spun staple yarns composed of the synthetic filaments having the characteristics previously noted, in conjunction of the four leaf 7 condition of fiaccidity and yieldability in the tape fabric, in the plane of the fabric, which is not subject to the internal strains which heretofore have been responsible for the undulatin of the corded edges of the foundation tapes of the prior art.

In fact, observanc of the functioning of fasteners employing the foundation tapes of the present invention appears to indicate that as the slide B is moved along the interlocking scoops b, b to effect progression of the interlocking of the successive disengaged scoops, a small degree of extensibility in the corded edges a, a to which the scoops b, b are secured, takes place. This characteristic facilitates the interlocking of the scoops b, b by the slide B and enables the slide 13 to be moved with a smooth easy motion along the tapes.

Any shrinkage differential which might be produced in adjacent longitudinal sections of the maximum amount of planar yieldability tape appears to be dissipated within the tape by reason of the relativ planar yieldability afforded the adjacent sections of the tape. Thus no undulating of the tapes occur and the tapes retain their fiat flaccid condition at all times.

lclaimz' l. A foundation tape for slide fasteners, comprising a narrow textile fabric composed of high tenacity synthetic staple of a length not less than 1%; inches and of a weight not in excess of 1% denier spun into yarns of not less than two or more than three ply twist, with said yarns exclusively constituting the warp and weft of the tape fabric interwoven in a four leaf twill pattern.

2. A foundation tape for slide fasteners, comprising a narrow textile fabric composed of high tenacity synthetic staple of a length not less than 1%; inches and of a weight not in excess of 1% denier spun into yarns of not les than two or more than three ply twist, with said yarns exclusively constituting the warp and weft of the tape fabric interwoven in a four leaf twill'pattern, said fabric having a thickness range between a minimum of .010 inch and a maximum of .028 inch.

3. A foundation tape for slide fasteners, com-- prising a narrow textile fabric composed of high tenacity synthetic staple of a length not less than 1 inches and of a weight not in excess of 1 /4 denier spun into yarns of not less than two or more than three ply twist, with said yams exclusively constituting the warpand weft of the tape fabric interwoven in a, four leaf twill pattern,"

said tapes being formed in widths of predetertern, with the lines of the pattern in laterally adjacent successive areas. disposed at relatively sharp angles'with respect to each other. This mined steps ranging from inch to 1 inch, and said warps having a range of breaking strength between a minimum of 40 lbs. and a maximum of lbs. propdrtional to said predetermined steps respectively in said width range. I

4. A foundation tape for slide fasteners comprising a narrow textile fabric composed of high twill weave, provides a aeoacae mum of 150 lbs. proportional to said predeten' tenacity synthetic staple of a length not less than 1 inches and of a weight not in excess of 1% denier spun into yarns of not less than two or more thanthree ply twist, with said yarns exclusively constituting the warp and weft of the tape fabric interwoven in a four leaf twill pattern, said tapes being formed in widths of predetermined steps ranging from inch to 1 inch, and said vwefts having a range of breaking strength from a minimum of 60 lbs. to a maximum of 150 lbs. proportional to said predetermined steps respectively in saidwidth range.

5. A foundation tape for slide fasteners, comprising a narrow textile fabric composed of high tenacity syntheticlstaple of a length not less than 11% inches and of a weight not in excess of 1%. denier spuninto yarns of not less than two or more than three ply twist, with said yarns exclusively constitutingthe warp and weft of the tape fabric interwoven in a four leaf twill pattern, said fabric having a thickness range between a minimum of .010 inch and a maximum of .028 inch, said tapes being formed in widths of predetermined steps ranging from inch to 1 inch, and said warps having a, range of breaking strength between a minimum of 40 lbs. and a maximum of 120 lbs. proportional to said predetermined steps respectively in said width range.

6. A foundation tape for slide fasteners, comprising a narrow textile fabric composed of high.

tenacity synthetic staple of a length not less than 11'; inches and of a weight not in excess of 1 A denier spun into yarns of not less than two or more than three ply twist, with said yarns exclusively constituting the warp and weft of the tape fabric interwoven in a four leaf twill pattern, said fabric having a thickness range between a minimum of, .010 inch and a maximum of .028 inch, said tapes being formed in widths of predetermined steps ranging from inch to 1 inch, and said wefts having a range of breaking strength from a minimum of lbs. to a maximined steps respectively in said width range.

7. A foundation tape for slide fasteners, comprising a narrow textile fabric composed of high tenacity synthetic staple of a length not less than. 1 inches and of a Weight not inexcess of 1 /4 denier spun into yarns of not less than two or more than three ply twist, with said yarns exclusively constituting the warp and weft of the tape fabric interwoven in a four leaf twill pattern, said tapes being formed in widths of predetermined steps ranging from inch to 1 inch,

said warps having a range of breaking strength between a minimum of 40 lbs. and a maximum of lbs. proportional to said predetermined steps respectively in said width range, and said wefts having a range of breaking strength from a minimum of 60 lbs. to a maximum of lbs. proportional to said predetermined steps respectively in said width range.

8. A foundation tape for slide fasteners, comprising a narrow textilefalbric composed of high tenacity synthetic staple of a length not less than 1?; inches and a weight not in excess of 1 A denier spun into yarns of not less than two or more than three ply twist, with said yarns ex-,

clusivelyconstituting the warp and weft of the tape fabric interwoven in a four leaf twill pattern, said fabric having a thickness range between a minimum of .010 inch and a maximum of .028 inch, said tapes being formed in widths of predetermined steps ranging from inch to 1 inch, said warps having a range of breaking strength between a minimum of 40 lbs. and a maximum of 120 lbs. proportional to said predetermined steps respectively in said width range, and said wefts having a range of breaking strength from a minimum of 60 lbs. to a maximum of 150 lbs. proportional to said predetermined steps respectively in said width-range. V JOHN E. FIFE, JR. 

